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ADEX Dental practice questions

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Question 1Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which cranial nerve provides the motor innervation to the muscles of mastication?

  1. Glossopharyngeal (IX)
  2. Trigeminal (V3) Correct answer.
  3. Hypoglossal (XII)
  4. Facial (VII)

Explanation

The muscles of mastication (masseter, temporalis, medial pterygoid, lateral pterygoid) arise from the first pharyngeal arch and are therefore innervated by the mandibular division of the trigeminal nerve. The same division also supplies the mylohyoid, anterior digastric, tensor veli palatini, and tensor tympani.

Question 2Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

What is the normal resting pH range of arterial blood?

  1. 7.20–7.30
  2. 7.35–7.45 Correct answer.
  3. 7.55–7.65
  4. 6.80–7.00

Explanation

Arterial pH is normally held between 7.35 and 7.45 by buffer systems, respiration, and renal bicarbonate handling. Values below 7.35 indicate acidemia and values above 7.45 indicate alkalemia.

Question 3Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which enzyme separates the two parental DNA strands at the replication fork?

  1. Topoisomerase
  2. DNA ligase
  3. Primase
  4. DNA helicase Correct answer.

Explanation

DNA helicase hydrolyzes ATP to break the hydrogen bonds between complementary bases, unwinding the duplex so each strand can serve as a template. The resulting single-stranded regions are stabilized by single-strand binding proteins.

Question 4Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which microorganism is regarded as the principal initiator of smooth-surface dental caries?

  1. Staphylococcus aureus
  2. Lactobacillus acidophilus
  3. Streptococcus pyogenes
  4. Streptococcus mutans Correct answer.

Explanation

Streptococcus mutans uses glucosyltransferases to build insoluble glucans from sucrose, which anchor the organism to the pellicle and promote a dense, acidogenic biofilm. Its ability to both produce acid rapidly and survive at low pH makes it the key initiator of enamel demineralization.

Question 5Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which immunoglobulin predominates in whole saliva and provides the main mucosal defense against pathogens?

  1. IgM
  2. Secretory IgA Correct answer.
  3. IgG
  4. IgE

Explanation

Secretory IgA is a dimer produced by plasma cells in the salivary glands and is joined by a J chain and the polymeric immunoglobulin receptor-derived secretory component. The secretory component protects it from proteolysis in the oral environment, allowing it to neutralize organisms and prevent mucosal adherence.

Question 6Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which finding is the earliest morphologic sign of reversible cell injury?

  1. Cellular swelling Correct answer.
  2. Dystrophic calcification
  3. Coagulative necrosis
  4. Nuclear pyknosis

Explanation

Impaired ATP production disables the sodium-potassium pump, so sodium and water enter the cell and cause hydropic swelling. This change reverses if the insult is removed before membrane integrity is lost.

Question 7Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

What is the mechanism by which aspirin produces its anti-inflammatory and antiplatelet effects?

  1. Irreversible acetylation of cyclooxygenase Correct answer.
  2. Reversible inhibition of cyclooxygenase
  3. Activation of phospholipase A2
  4. Blockade of the lipoxygenase pathway

Explanation

Aspirin covalently acetylates a serine residue in the active site of cyclooxygenase-1 and cyclooxygenase-2, permanently inactivating the enzyme. Because platelets cannot synthesize new protein, this irreversible block explains the prolonged bleeding time after aspirin exposure.

Question 8Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

The inferior alveolar nerve reaches the mandibular teeth by entering which foramen?

  1. Mental foramen
  2. Incisive foramen
  3. Mandibular foramen Correct answer.
  4. Infraorbital foramen

Explanation

The inferior alveolar nerve descends medial to the ramus and enters the mandibular foramen on the medial surface of the ramus to run within the mandibular canal. It supplies the mandibular teeth and exits anteriorly at the mental foramen as the mental nerve.

Question 9Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Clearance of which substance is used as the reference standard for measuring glomerular filtration rate?

  1. Inulin Correct answer.
  2. Glucose
  3. Creatinine
  4. Para-aminohippurate

Explanation

Inulin is freely filtered at the glomerulus and is neither reabsorbed nor secreted by the tubules, so its clearance equals the filtration rate. Creatinine clearance approximates GFR but slightly overestimates it because of tubular secretion.

Question 10Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which action explains the local anesthetic effect of lidocaine on a peripheral nerve?

  1. Blockade of voltage-gated sodium channels Correct answer.
  2. Agonism at GABA-A receptors
  3. Closure of voltage-gated potassium channels
  4. Inhibition of acetylcholinesterase

Explanation

Lidocaine binds the inner pore of voltage-gated sodium channels in the open or inactivated state, preventing the sodium influx required to reach threshold and propagate an action potential. The block is use-dependent, so rapidly firing fibers are affected most.

Question 11Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which bacterial component is responsible for the fever and shock seen in gram-negative sepsis?

  1. Lipopolysaccharide Correct answer.
  2. Pili
  3. Teichoic acid
  4. Peptidoglycan

Explanation

Lipopolysaccharide in the outer membrane of gram-negative bacteria signals through TLR4 on macrophages, triggering release of TNF, IL-1, and IL-6. The lipid A portion is the toxic moiety that drives fever, hypotension, and disseminated intravascular coagulation.

Question 12Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which complement fragment acts as the major opsonin promoting phagocytosis of bacteria?

  1. C5a
  2. C3a
  3. C9
  4. C3b Correct answer.

Explanation

C3b covalently binds microbial surfaces and is recognized by complement receptors on neutrophils and macrophages, greatly enhancing phagocytosis. This opsonization is the dominant protective function of complement against encapsulated organisms.

Question 13Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which enzyme catalyzes the rate-limiting step of glycolysis?

  1. Glucose-6-phosphatase
  2. Pyruvate kinase
  3. Phosphofructokinase-1 Correct answer.
  4. Hexokinase

Explanation

Phosphofructokinase-1 converts fructose-6-phosphate to fructose-1,6-bisphosphate and is the committed, rate-limiting step of glycolysis. It is allosterically activated by AMP and fructose-2,6-bisphosphate and inhibited by ATP and citrate.

Question 14Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which cell types predominate in an established chronic inflammatory infiltrate?

  1. Mast cells and basophils
  2. Neutrophils and eosinophils
  3. Neutrophils and plasma cells
  4. Macrophages and lymphocytes Correct answer.

Explanation

Chronic inflammation is characterized by mononuclear cells, chiefly macrophages that orchestrate fibrosis and tissue remodeling along with lymphocytes and plasma cells. Neutrophils dominate acute inflammation and are usually sparse after the first few days.

Question 15Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which vessel supplies the maxillary posterior teeth and the buccal gingiva adjacent to them?

  1. Posterior superior alveolar artery Correct answer.
  2. Inferior alveolar artery
  3. Facial artery
  4. Lingual artery

Explanation

The posterior superior alveolar artery arises from the maxillary artery in the pterygopalatine fossa and enters the posterior maxilla through the alveolar canals. It supplies the maxillary molars, premolars, and overlying buccal tissues.

Question 16Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which action of parathyroid hormone directly raises the serum calcium concentration?

  1. Inhibition of renal calcium reabsorption
  2. Reduction of intestinal calcium absorption
  3. Stimulation of osteoclastic resorption Correct answer.
  4. Increased renal phosphate retention

Explanation

Parathyroid hormone signals osteoblasts to upregulate RANKL, which promotes osteoclast formation and bone resorption, releasing calcium and phosphate into the circulation. It also increases distal tubular calcium reabsorption and stimulates renal 1-alpha-hydroxylase to raise calcitriol and intestinal absorption.

Question 17Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which regimen is recommended for infective endocarditis prophylaxis before a dental extraction in a patient with a prosthetic heart valve?

  1. Amoxicillin 500 mg orally 1 hour after the procedure
  2. Amoxicillin 2 g orally 30–60 minutes before Correct answer.
  3. Erythromycin 250 mg orally 24 hours before
  4. Clindamycin 600 mg orally once weekly for one week before

Explanation

Current guidelines recommend a single 2 g oral dose of amoxicillin 30 to 60 minutes before the procedure for eligible high-risk patients who can take oral medication. The goal is a peak blood level during the transient bacteremia caused by the procedure.

Question 18Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Herpes simplex virus type 1 establishes lifelong latency in which anatomical site?

  1. Submandibular lymph nodes
  2. Trigeminal ganglion Correct answer.
  3. Dorsal root ganglia of the lumbar spine
  4. Parotid gland

Explanation

After primary orolabial infection, HSV-1 travels by retrograde axonal transport to the trigeminal ganglion, where it remains latent. Reactivation with anterograde transport along the same sensory branches produces recurrent cold sores at the mucocutaneous junction.

Question 19Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Vitamin C is required as a cofactor for which reaction in connective tissue repair?

  1. Vitamin K–dependent gamma-carboxylation of glutamate
  2. Conversion of pyruvate to acetyl-CoA
  3. Hydroxylation of proline and lysine in collagen Correct answer.
  4. Absorption of calcium in the duodenum

Explanation

Ascorbate maintains the ferrous iron in prolyl and lysyl hydroxylase, allowing hydroxylation of proline and lysine residues so collagen triple helices can cross-link. Deficiency produces fragile collagen, causing bleeding gums and impaired wound healing in scurvy.

Question 20Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which components characterize granulation tissue in a healing extraction socket?

  1. Adipose tissue and cartilage
  2. Necrotic debris with neutrophils
  3. Proliferating capillaries and fibroblasts Correct answer.
  4. Dense collagen with few cells

Explanation

Granulation tissue consists of newly budding capillaries, proliferating fibroblasts, and a mixed inflammatory infiltrate that together fill the defect and lay down new matrix. Its rich vascularity gives the reddish, granular appearance from which the name derives.

Question 21Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

In a patient with uncomplicated metabolic acidosis from diabetic ketoacidosis, which respiratory response is expected?

  1. Increased ventilation with reduced PaCO2 Correct answer.
  2. Decreased ventilation with increased PaCO2
  3. Increased renal bicarbonate excretion
  4. Reduced renal hydrogen ion secretion

Explanation

The fall in plasma bicarbonate lowers pH and stimulates peripheral chemoreceptors, producing deep rapid breathing that lowers PaCO2 and partially restores the bicarbonate-to-carbonic acid ratio. Renal compensation, by contrast, increases hydrogen ion secretion and bicarbonate reabsorption but develops over days.

Question 22Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

A drug follows first-order elimination with a half-life of 6 hours and is given by constant intravenous infusion. Approximately when will steady-state plasma concentration be reached?

  1. 24–30 hours Correct answer.
  2. 48–60 hours
  3. 6 hours
  4. 3 hours

Explanation

With first-order kinetics, approximately 50 percent of steady state is reached after one half-life, 75 percent after two, and over 94 percent after four to five half-lives. For a 6-hour half-life, that corresponds to roughly 24 to 30 hours.

Question 23Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

How does a competitive inhibitor alter the kinetic parameters of an enzyme?

  1. Km decreased, Vmax unchanged
  2. Km increased, Vmax decreased
  3. Km unchanged, Vmax decreased
  4. Km increased, Vmax unchanged Correct answer.

Explanation

A competitive inhibitor binds reversibly at the active site, so higher substrate concentrations can outcompete it and the maximal velocity is preserved. More substrate is therefore needed to reach half-maximal velocity, which is expressed as an increased apparent Km.

Question 24Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which statement correctly describes antigen presentation by MHC class II molecules?

  1. MHC class I presents to CD4+ T cells
  2. MHC class II presents to CD8+ T cells
  3. MHC class II presents to CD4+ T cells Correct answer.
  4. MHC class I presents peptides to B-cell receptors

Explanation

MHC class II molecules are expressed on professional antigen-presenting cells and display peptides derived from endocytosed extracellular material to CD4+ helper T cells. This interaction is central to activating helper T cells that then license B cells and macrophages.

Question 25Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which set of conditions constitutes Virchow's triad for thrombus formation?

  1. Fibrosis, calcification, necrosis
  2. Venous stasis, endothelial injury, hypercoagulability Correct answer.
  3. Thrombocytopenia, hypofibrinogenemia, vasospasm
  4. Arterial dilation, anemia, hypothermia

Explanation

Virchow's triad describes the three factors that predispose to thrombosis: abnormal blood flow such as stasis or turbulence, injury to the endothelium, and a hypercoagulable state. Any one factor may be sufficient, and the risks are additive when several coexist.

Question 26Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which nerve provides the motor innervation to the muscles of mastication?

  1. Motor root of the facial nerve
  2. Maxillary division of the trigeminal nerve
  3. Motor fibers of the glossopharyngeal nerve
  4. Mandibular division of the trigeminal nerve Correct answer.

Explanation

The muscles of mastication (masseter, temporalis, medial and lateral pterygoids, plus the anterior digastric, mylohyoid and tensor veli palatini) develop from the first pharyngeal arch and therefore carry their motor supply in the mandibular division of the trigeminal nerve. The nerve exits the skull through the foramen ovale and gives off branches such as the masseteric and deep temporal nerves before continuing as the inferior alveolar and lingual nerves. The maxillary division is entirely sensory, and the facial and glossopharyngeal nerves supply muscles of the second and third arches, respectively.

Question 27Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which microorganism is regarded as the principal etiologic agent of coronal dental caries in humans?

  1. Streptococcus mutans Correct answer.
  2. Staphylococcus epidermidis
  3. Actinomyces israelii
  4. Lactobacillus acidophilus

Explanation

Mutans streptococci, chiefly Streptococcus mutans and Streptococcus sobrinus, are the principal initiators of coronal caries. They adhere to the acquired pellicle, use glucosyltransferases to build sticky glucans from sucrose, and ferment dietary sugars into lactic acid that demineralizes enamel beneath the plaque biofilm. Lactobacilli and Actinomyces contribute to lesion progression and to root caries but are not the primary initiating organisms.

Question 28Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

A patient whose anticoagulation has been stable on warfarin is prescribed a course of metronidazole for an odontogenic infection. Which mechanism best explains the expected rise in INR?

  1. Inhibition of CYP2C9-mediated metabolism of warfarin Correct answer.
  2. Displacement of warfarin from its plasma protein binding sites
  3. Induction of hepatic enzymes that accelerate warfarin clearance
  4. Enhanced renal clearance of the active warfarin enantiomer

Explanation

Warfarin is cleared mainly by hepatic cytochrome P450 enzymes, with the more potent S-enantiomer metabolized largely by CYP2C9. Metronidazole inhibits CYP2C9, so warfarin accumulates and the prothrombin time/INR rises, increasing bleeding risk. When this combination is unavoidable, the warfarin dose is reduced and the INR is monitored closely.

Question 29Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

Which nephron segment reabsorbs sodium mainly through the Na–K–2Cl cotransporter while remaining essentially impermeable to water?

  1. Distal convoluted tubule
  2. Proximal convoluted tubule
  3. Thick ascending limb of the loop of Henle Correct answer.
  4. Descending thin limb of the loop of Henle

Explanation

The thick ascending limb uses the apical Na–K–2Cl (NKCC2) cotransporter to move solute out of the lumen while its water permeability is very low, so tubular fluid becomes dilute and the medullary interstitium becomes hypertonic. This is the basis of countercurrent multiplication and the site at which loop diuretics act. The other segments either reabsorb water freely or use different sodium transporters.

Question 30Biomedical Sciences (anatomy, physiology, biochemistry, microbiology, immunology, general pathology, pharmacology)

A young child has recurrent abscesses caused by Staphylococcus aureus and pulmonary Aspergillus infection, and a nitroblue tetrazolium test shows no neutrophil color change. Which process is most likely defective?

  1. Somatic hypermutation of immunoglobulin genes in B cells
  2. Assembly of the complement membrane attack complex
  3. Fusion of phagosomes with lysosomes after ingestion
  4. Superoxide generation by the phagocyte NADPH oxidase Correct answer.

Explanation

The nitroblue tetrazolium test depends on superoxide produced during the neutrophil respiratory burst, so failure of dye reduction points to defective NADPH oxidase, the defect of chronic granulomatous disease. Phagocytes ingest organisms normally but cannot kill catalase-positive species that supply little of their own hydrogen peroxide, which explains the characteristic susceptibility to Staphylococcus aureus, Aspergillus and Nocardia. The condition is diagnosed by oxidase testing or genetic analysis and managed with antimicrobial prophylaxis and interferon-gamma.

Question 31Diagnosis and Treatment Planning, including oral and maxillofacial radiology

Bitewing radiographs are most useful for detecting which of the following?

  1. Impacted mandibular third molars
  2. Osseous changes of the temporomandibular joint
  3. Interproximal dental caries Correct answer.
  4. Periapical cysts

Explanation

Bitewings show the crowns of posterior teeth and the adjacent alveolar crest without significant superimposition. This makes them the preferred intraoral image for interproximal caries and early crestal bone loss. Periapical lesions, impactions, and TMJ changes require other projections.

Question 32Diagnosis and Treatment Planning, including oral and maxillofacial radiology

Which of the following appears most radiolucent on a dental radiograph?

  1. Amalgam
  2. Air Correct answer.
  3. Enamel
  4. Cortical bone

Explanation

Radiolucency reflects low attenuation of x-rays: the less dense the material, the darker the image. Air attenuates very few x-rays and is therefore the most radiolucent of the listed materials. Enamel, cortical bone, and amalgam are increasingly radiopaque.

Question 33Diagnosis and Treatment Planning, including oral and maxillofacial radiology

A positive response to a cold thermal test most directly indicates which of the following?

  1. The tooth is nonvital
  2. The pulp is infected
  3. The tooth is free of periapical disease
  4. Some sensory nerve function remains Correct answer.

Explanation

Cold testing stimulates A-delta nerve fibers, so a positive response shows that sensory innervation is at least partly intact. It does not prove the pulp is healthy, infected, or free of apical disease. Pulp diagnosis combines testing with history, percussion, palpation, and radiographs.

Question 34Diagnosis and Treatment Planning, including oral and maxillofacial radiology

A patient with well-controlled type 2 diabetes and no functional limitations is best classified as which ASA physical status?

  1. ASA IV
  2. ASA III
  3. ASA II Correct answer.
  4. ASA I

Explanation

ASA II describes a patient with mild systemic disease and no functional limitation, which fits well-controlled diabetes. ASA I is a healthy patient without systemic disease. ASA III denotes severe systemic disease with functional limitation, and ASA IV denotes a life-threatening condition.

Question 35Diagnosis and Treatment Planning, including oral and maxillofacial radiology

What is a principal advantage of cone-beam computed tomography over panoramic radiography?

  1. It replaces the need for clinical examination
  2. It always delivers a lower radiation dose
  3. It requires no patient positioning
  4. 3D visualization without superimposition Correct answer.

Explanation

CBCT reconstructs volumetric data, allowing structures to be viewed in axial, coronal, and sagittal planes without the superimposition inherent in panoramic images. Its dose is generally higher than a panoramic radiograph, and careful positioning remains necessary. Imaging never replaces clinical examination.

Question 36Diagnosis and Treatment Planning, including oral and maxillofacial radiology

Which of the following provides the definitive diagnosis of a suspected oral mucosal malignancy?

  1. Incisional biopsy with histopathology Correct answer.
  2. Panoramic radiography
  3. Clinical inspection with toluidine blue staining
  4. Fine-needle aspiration cytology

Explanation

Histopathologic examination of a representative tissue specimen is the diagnostic standard for suspected mucosal malignancy. Toluidine blue and clinical inspection are aids, not definitive tests. Fine-needle aspiration is useful for selected masses, and panoramic radiography shows bone rather than mucosal histology.

Question 37Diagnosis and Treatment Planning, including oral and maxillofacial radiology

A tooth has a deep carious lesion, no response to cold, tenderness to percussion, and a periapical radiolucency. Which diagnosis is most consistent?

  1. Reversible pulpitis
  2. Necrotic pulp with apical periodontitis Correct answer.
  3. Normal pulp with a healthy periodontium
  4. Irreversible pulpitis without apical involvement

Explanation

Loss of response to cold indicates that the pulp is necrotic, and percussion tenderness plus a periapical radiolucency indicate apical periodontitis. Reversible pulpitis would respond normally to cold and lack apical findings. Irreversible pulpitis typically retains an exaggerated or lingering response.

Question 38Diagnosis and Treatment Planning, including oral and maxillofacial radiology

A panoramic radiograph shows a blurred radiopacity in the upper contralateral region that does not correspond to an anatomic structure. What is the most likely explanation?

  1. A mandibular torus
  2. A sensor or film artifact
  3. A normal anatomic landmark
  4. Ghost image of a contralateral object Correct answer.

Explanation

Structures outside the focal trough can produce ghost images on the opposite side, typically higher and magnified or blurred. A true anatomic landmark would appear in its expected location and shape. A mandibular torus would appear near the mandible, not as a contralateral upper opacity.

Question 39Diagnosis and Treatment Planning, including oral and maxillofacial radiology

Which clinical situation most clearly justifies a limited-field CBCT rather than periapical radiographs?

  1. Detecting interproximal caries in posterior teeth
  2. Buccolingual localization of an impacted canine Correct answer.
  3. Annual monitoring of crestal bone loss
  4. Routine caries screening in a child

Explanation

Localizing an impacted canine requires three-dimensional assessment of its buccolingual position and its relationship to adjacent roots, which CBCT provides. Caries detection and routine bone monitoring are generally accomplished with lower-dose intraoral images. The principle of ALARA favors the smallest field and lowest dose that answer the clinical question.

Question 40Diagnosis and Treatment Planning, including oral and maxillofacial radiology

A well-defined unilocular radiolucency surrounding the crown of an impacted mandibular third molar in a 22-year-old is most consistent with which diagnosis?

  1. Odontogenic keratocyst
  2. Ameloblastoma
  3. Dentigerous cyst Correct answer.
  4. Central giant cell granuloma

Explanation

A dentigerous cyst encloses the crown of an unerupted tooth and attaches at the cementoenamel junction; impacted third molars are a common site. Odontogenic keratocysts tend to grow along the bone with minimal expansion, ameloblastomas are often multilocular, and central giant cell granulomas favor the anterior mandible.

Question 41Diagnosis and Treatment Planning, including oral and maxillofacial radiology

A patient taking warfarin with a reported INR of 2.5 needs a simple extraction. Which is the most appropriate initial step?

  1. Stop warfarin 7 days before surgery without consulting the prescriber
  2. Double the warfarin dose after the extraction
  3. Check INR and coordinate with the prescriber Correct answer.
  4. Proceed without checking the INR because simple extractions do not bleed

Explanation

Patients on warfarin are managed with a current INR and communication with the clinician who prescribes the anticoagulant. Simple extractions can often be performed with local hemostatic measures when the INR is within an acceptable range. Unilateral discontinuation or dose changes can cause thromboembolic harm.

Question 42Diagnosis and Treatment Planning, including oral and maxillofacial radiology

A patient has a 2-mm discrepancy between centric relation and maximum intercuspation and reports no symptoms. What is the most appropriate interpretation?

  1. It indicates a mandibular fracture
  2. It always requires immediate full-mouth rehabilitation
  3. It confirms temporomandibular joint ankylosis
  4. Common and not requiring treatment by itself Correct answer.

Explanation

Small centric relation to maximum intercuspation discrepancies are common and are not pathologic by themselves. Treatment is directed at the patient's symptoms and functional needs, not the number alone. Ankylosis and fracture have distinct clinical and radiographic findings.

Question 43Diagnosis and Treatment Planning, including oral and maxillofacial radiology

Which patient most clearly meets current criteria for antibiotic prophylaxis before invasive dental procedures?

  1. A patient with a prosthetic hip
  2. A patient with well-controlled hypertension
  3. Prior infective endocarditis Correct answer.
  4. A patient with type 2 diabetes

Explanation

Current cardiac prophylaxis guidelines include a history of infective endocarditis, prosthetic cardiac valves, certain congenital heart defects, and cardiac transplant valvulopathy. Prosthetic joints and well-controlled diabetes or hypertension are not routine indications. Prophylaxis decisions should follow the most current national guidelines.

Question 44Diagnosis and Treatment Planning, including oral and maxillofacial radiology

A patient has active periodontal disease and several carious teeth. Which phase of treatment should come first after emergency care?

  1. Orthodontic alignment
  2. Final crown cementation
  3. Cause-related therapy and caries control Correct answer.
  4. Implant placement

Explanation

Treatment planning proceeds from emergency care to a control phase that addresses infection, hygiene, and caries, followed by re-evaluation before definitive care. Implants, final restorations, and orthodontics are deferred until disease is controlled. Sequencing in this way improves predictability and avoids treating on an unstable foundation.

Question 45Diagnosis and Treatment Planning, including oral and maxillofacial radiology

Which imaging modality best demonstrates osseous detail of the temporomandibular joint?

  1. Cone-beam CT Correct answer.
  2. Magnetic resonance imaging
  3. Ultrasound
  4. Panoramic radiography

Explanation

CBCT provides high-contrast, thin-slice images of the condyle and glenoid fossa and is preferred for osseous TMJ evaluation. MRI is superior for soft-tissue structures such as the articular disc. Panoramic images superimpose the joint, and ultrasound has limited intra-articular usefulness.

Question 46Diagnosis and Treatment Planning, including oral and maxillofacial radiology

A panoramic radiograph shows the anterior teeth blurred and narrowed. What is the most likely cause?

  1. The sensor moved during the exposure
  2. The patient was positioned too far anterior to the focal trough Correct answer.
  3. The patient was positioned too far posterior to the focal trough
  4. The exposure time was too long

Explanation

When the patient is positioned too far anterior to the focal trough, the anterior teeth fall outside the sharp zone and appear blurred and narrowed. The opposite positioning error tends to widen the anterior teeth. Sensor movement and exposure time produce different artifacts, such as distortion or altered density.

Question 47Diagnosis and Treatment Planning, including oral and maxillofacial radiology

Multiple well-defined radiolucencies at the apices of mandibular anterior teeth in a middle-aged Black woman with vital teeth most likely represent which condition?

  1. Periapical cyst associated with a nonvital tooth
  2. Central giant cell granuloma of the mandible
  3. Ameloblastoma of the posterior mandible
  4. Periapical cemento-osseous dysplasia Correct answer.

Explanation

Periapical cemento-osseous dysplasia commonly affects the anterior mandible of middle-aged Black women, and the teeth remain vital. Early lesions are radiolucent and later become mixed or radiopaque. Because the condition is benign and self-limiting, unnecessary endodontic treatment should be avoided.

Question 48Diagnosis and Treatment Planning, including oral and maxillofacial radiology

A patient received head and neck radiation two years ago and now needs a mandibular molar extracted. Which consideration is most important?

  1. The extraction should be performed without any antibiotics
  2. Increased osteoradionecrosis risk; coordinate planning Correct answer.
  3. No special precautions are needed after two years
  4. Orthodontic extraction is contraindicated

Explanation

Prior head and neck radiation causes hypovascular, hypoxic bone and increases the risk of osteoradionecrosis after extraction. Planning should involve the radiation oncologist and include atraumatic technique, primary closure when possible, and infection control. The risk does not disappear simply because two years have passed.

Question 49Diagnosis and Treatment Planning, including oral and maxillofacial radiology

A multilocular radiolucency with a soap-bubble appearance in the posterior mandible of a 35-year-old is most consistent with which diagnosis?

  1. Periapical cemento-osseous dysplasia
  2. Dentigerous cyst
  3. Odontoma
  4. Ameloblastoma Correct answer.

Explanation

Ameloblastoma classically produces a multilocular, soap-bubble radiolucency in the posterior mandible of a young to middle-aged adult. A dentigerous cyst is usually unilocular and surrounds an unerupted crown, while an odontoma is a mixed radiopaque lesion. Periapical cemento-osseous dysplasia occurs at anterior tooth apices.

Question 50Diagnosis and Treatment Planning, including oral and maxillofacial radiology

A patient has a suspected root fracture in a previously endodontically treated maxillary premolar, but periapical radiographs are inconclusive. Which is the most appropriate next imaging study?

  1. Bitewing radiograph
  2. Limited-field CBCT Correct answer.
  3. Panoramic radiograph
  4. Sialography

Explanation

Limited-field CBCT provides three-dimensional resolution and is more sensitive than conventional radiographs for root fractures, especially in endodontically treated teeth. Panoramic and bitewing images add little when the fracture is not visible on a periapical view. Sialography evaluates salivary ducts, not dental roots.